A270251 - OEIS

A270251

Number of n X n X n triangular 0..2 arrays with some element plus some adjacent element totalling 2 exactly once.

0, 12, 66, 468, 3612, 40020, 601368, 12473568, 355574028, 13968754800, 756926837340, 56646343727400, 5861182843734528, 839281074844449036, 166460255072308752300, 45762947464712474066844, 17450184715500929336251344, 9234511286693885324713350780, 6785336611707198855172238584884

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OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..24

EXAMPLE

Some solutions for n=4:

.....2........2........1........0........0........2........0........2

....2.1......2.1......2.2......0.0......1.0......2.1......1.0......2.1

...2.1.2....1.2.2....1.2.2....0.0.0....1.0.1....2.1.2....0.0.1....2.2.2

..2.2.2.1..1.2.1.2..0.2.2.1..0.1.1.0..0.0.0.0..2.2.2.2..1.0.1.2..1.1.2.2

CROSSREFS

Column 2 of A270256.

Sequence in context: A003200 A353291 A200190 * A165107 A032167 A039925

Adjacent sequences: A270248 A270249 A270250 * A270252 A270253 A270254

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 14 2016

STATUS

approved